This invention relates to a simple and precise way of identifying position and/or speed of a moving panel, such as a vehicle closure.
Vehicles are provided with moving closures such as windows, sunroofs, moonroofs, etc. In the prior art, these devices are typically powered by an electric motor driving the closure through some form of mechanical connection. One concern with such connections is that the closures are typically powered to close upon the actuation of a switch. Thus, an operator of a vehicle may actuate a switch to instruct the closure to move to a fully closed position. In those conditions, it is desirable to know the position of the moving panel at all times during the closing maneuver, for example in order to recognize the normal approach of end of travel as opposed to the presence of an obstacle in the path.
More recently, the inventor of the present application has invented a unique linear motor drive for a vehicle closure. This invention is disclosed in co-pending patent application Ser. No. 09/498,401 filed Feb. 4, 2000, and entitled xe2x80x9cIntegral Linear Motorxe2x80x9d. This invention includes a moving magnet that moves with the closure and an electric linear stator formed by a plurality of rungs arranged in a ladder-like fashion. The type of motor disclosed in the above-referenced application may be modified to provide position and/or speed feedback.
In a disclosed embodiment of this invention, the stator for a linear motor for driving a vehicle closure is arranged in such a fashion that the rungs are distinct. In this way, a control can identify the particular position of the closure, and/or can also determine velocity information. From the velocity and position information the control can also assist an appropriate detection device in identifying the presence of an obstruction.
In one embodiment, the distance between the rungs is modified such that the distance between each pair of rungs is individually different. In this way, the control can sense the distance between two adjacent rungs, and know precisely where the closure is in its path of movement. This can also be utilized to determine velocity of the moving closure. Once velocity is known, an obstruction can also be identified through an appropriate detection device. In this way, an obstruction can be predicted early in the path of the closure, and before the closure begins to pinch the obstruction. Notably, the obstruction is the most typically a passenger""s body part, and thus it is desirable to identify the obstruction as early as possible.
In other embodiments, the shape of wires at any one of the rungs can be modified such that each rung can be individually identified.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.